These drugs have shown definite antitumor activity but are still classified as investigational for a variety of reasons.
• The trials seeking FDA approval may be incomplete or currently inconclusive.
• A drug sponsor has not been identified or is under negotiation.
• The circumstances in which the drug has been shown to be useful do not easily lend themselves to the drug
approval process, so approval is no longer being sought.
For oncologists registered in good standing as clinical investigators, drugs in the last two categories are often obtainable through the National Cancer Institute . Drugs are also available—rarely—from industry sponsors for "compassionate" use. In other instances, a referral to an ongoing clinical trial will allow entry into a randomized study, generally with a 50-50 chance of receiving the experimental treatment.
Amsacrine is distributed by the NCI for the treatment of resistant acute leukemias. It is chemically related to drugs such as doxorubicin . It has a generally favorable toxicity profile but less activity against all other tumors. It is still being tested in various combinations against malignant lymphomas.
Azacitidine is also an antileukemic agent distributed by the NCI for some resistant leukemias.
